C-H activation generates period-shortening molecules that target cryptochrome in the mammalian circadian clock.

The synthesis and functional analysis of KL001 derivatives, which are modulators of the mammalian circadian clock, are described. By using cutting-edge C-H activation chemistry, a focused library of KL001 derivatives was rapidly constructed, which enabled the identification of the critical sites on KL001 derivatives that induce a rhythm-changing activity along with the components that trigger opposite modes of action. The first period-shortening molecules that target the cryptochrome (CRY) were thus discovered.

Glycinergic transmission and postsynaptic activation of CaMKII are required for glycine receptor clustering in vivo.

Synaptic transmission-dependent regulation of neurotransmitter receptor accumulation at postsynaptic sites underlies the formation, maintenance and maturation of synaptic function. Previous in vitro studies showed that glycine receptor (GlyR) clustering requires synaptic inputs. However, in vivo GlyR regulation by synaptic transmission is not fully understood.

Defective glycinergic synaptic transmission in zebrafish motility mutants.

Glycine is a major inhibitory neurotransmitter in the spinal cord and brainstem. Recently, in vivo analysis of glycinergic synaptic transmission has been pursued in zebrafish using molecular genetics. An ENU mutagenesis screen identified two behavioral mutants that are defective in glycinergic synaptic transmission.

Development of the circadian oscillator during differentiation of mouse embryonic stem cells in vitro.

The molecular oscillations underlying the generation of circadian rhythmicity in mammals develop gradually during ontogenesis. However, the developmental process of mammalian cellular circadian oscillator formation remains unknown. In differentiated somatic cells, the transcriptional-translational feedback loops (TTFL) consisting of clock genes elicit the molecular circadian oscillation.

Real-time monitoring of circadian clock oscillations in primary cultures of mammalian cells using Tol2 transposon-mediated gene transfer strategy.

Background: The circadian rhythm in mammals is orchestrated by a central pacemaker in the brain, but most peripheral tissues contain their own intrinsic circadian oscillators. The circadian rhythm is a fundamental biological system in mammals involved in the regulation of various physiological functions such as behavior, cardiovascular functions and energy metabolism. Thus, it is important to understand the correlation between circadian oscillator and physiological functions in peripheral tissues.

Mini screening of kinase inhibitors affecting period-length of mammalian cellular circadian clock.

In mammalian circadian rhythms, the transcriptional-translational feedback loop (TTFL) consisting of a set of clock genes is believed to elicit the circadian clock oscillation. The TTFL model explains that the accumulation and degradation of mPER and mCRY proteins control the period-length (tau) of the circadian clock. Although recent studies revealed that the Casein Kinase I epsilon delta (CKI epsilon delta) regulates the phosphorylation of mPER proteins and the circadian period-length, other kinases are also likely to contribute the phosphorylation of mPER.

Presence of robust circadian clock oscillation under constitutive over-expression of mCry1 in rat-1 fibroblasts.

In mammals, mCRY proteins are essential and are major negative elements in circadian feedback loops. In this study, robust circadian clock oscillation was present even under conditions with constitutive over-expression of mCry1 in rat-1 cells. Rat-1 cells were produced to stably express mPer2 promoter-driven luciferase reporter, in which mCry1 was overexpressed under a tetracycline-dependent gene expression (Tet-On) system.

The BMAL1 C terminus regulates the circadian transcription feedback loop.

The circadian clock is driven by cell-autonomous transcription/translation feedback loops. The BMAL1 transcription factor is an indispensable component of the positive arm of this molecular oscillator in mammals. Here, we present a molecular genetic screening assay for mutant circadian clock proteins that is based on real-time circadian rhythm monitoring in cultured fibroblasts.

Rhythmic post-transcriptional regulation of the circadian clock protein mPER2 in mammalian cells: a real-time analysis.

Post-transcriptional/translational mechanisms regulate the circadian clock system of many organisms, including mammals. The level of the essential clock protein mPER2 daily oscillates in peripheral cells as well as in neurons of the master oscillator in the suprachiasmatic nucleus (SCN). Post-translational modifications of mPER2, such as phosphorylation and ubiquitination, are likely involved in the regulation of its stability and intracellular accumulation rhythms, which in turn create an approximately 2-4 h delay from the rhythm of mPer2 mRNA.